NTB: zero PCI driver data

Zero pci_device_id driver_data variable.  Unused, but 'EXTRA_CFLAGS=-W'
complained of uninitialized variables.

Signed-off-by: Jon Mason <jon.mason@intel.com>
NTB: declare unused variables

Tag pci_device_id in ntb_pci_probe as unused function parameters.  This
corrects issues found by 'EXTRA_CFLAGS=-W'.

Signed-off-by: Jon Mason <jon.mason@intel.com>
ntb_netdev: declare unused variables and fix missing initializer

Tag qp in ntb_netdev_tx_handler and net_device in ntb_get_settings as
unused function parameters.  Also, correct missing initializer errors
for 'struct device_driver' in ntb_netdev_client.  This corrects issues
found by 'EXTRA_CFLAGS=-W'.

Signed-off-by: Jon Mason <jon.mason@intel.com>